About 100,000 thunderstorms strike each year in the U.S., according to the National Weather Service. Every one of them is dangerous because all thunderstorms produce lightning, as well as possible heavy rain, flash flooding, strong winds, hail and tornadoes.

Lightning is most dangerous to people who are outdoors, especially under or near tall trees; in or on water; or on or near hilltops.

If you're stuck outdoors when lightning flashes:

Find a low spot away from trees, fences and poles that is not subject to flooding

If you're in the woods, take shelter under shorter trees.

If you feel your skin tingle or your hair stand on end, squat low to the ground on the balls of your feet. Place your hands on your knees with your head between them. Make yourself the smallest target possible, and minimize your contact with the ground.

If you're boating or swimming, get to land and find shelter immediately.